The invention concerns a steering column assembly for arranging in the area of a steering column in a motor vehicle, comprising a locating device, a centrally arranged support board and at least one steering column switch, whereby the locating device comprises a receptacle for the support board and at least one laterally-aligned receptacle for the steering column switch; and whereby the support board establishes the electrical connection between the connections of the steering column switch and the control devices of the vehicle allocated to the steering column switch; and whereby the control devices allocated to the steering column switch are at least in part arranged on the support board. Such a locating device is for example known from EP 0 763 447 A2.
Switches arranged on a steering column assembly are used to operate and control various functions of the vehicle. Such functions can for example be switching the vehicle lights on and off, initiating the turn signals or the windscreen wiper device, operating an automatic cruise control etc. The intention is to allow operation and control of as many functions of a vehicle as possible in close proximity to the steering wheel. Such an arrangement ensures that the driver can reach the controls without having to take whichever hand is necessary for operating the control away from the steering wheel region.
Apart from increasing operational safety, another requirement is simplification in manufacture and assembly of the elements necessary for operating and controlling the various functions. This applies in particular to such components of the switches concerned which are exposed to premature destruction or increased wear.
In its diagram for the state of the art, EP 0 763 447 A2 shows a steering column lever with a locating device attachable to the steering column of a motor vehicle, with two laterally-aligned seats for two steering column switches to which a centrally arranged support board is allocated. This support board on the one hand establishes electrical connections between the connections of the steering column switch and the vehicle's control devices which are allocated to the steering column switch, whereby on the other hand the control devices allocated to the steering column switch are at least partly arranged on the support board. In the known locating device, the electrical connection between the connections of the steering column switch and the support board takes place via plugs which can be plugged into the support board; these plugs are connected via cables to the contacts of the steering column switches. With the steering column assembly known from EP 0 763 447 A2, the support board is essentially configured in a circular shape; it is positioned into the respective receptacle of the locating device in the direction of the axis of the steering column.
A further embodiment of a steering column assembly is known from DE 44 28 883 C1. This steering column assembly too comprises a locating device, a centrally arranged support board and two steering column switches. Here too, the support board is inserted as a ring-shaped component into a receptacle formed in the front of the locating device and aligned coaxially to the longitudinal axis of the steering column assembly. At the same time, the steering column switches with electrical control elements form a firmly interconnected modular unit. The support board comprises press contacts which are laterally formed to it; by way of the said press contacts the contact surfaces of the electrical connections of the respective modular unit comprising steering column switch and switches, can be connected to the strip conductors of the support board. The strip conductors of the support board are connected to plug-in contacts fixed to the support board which, with the support board plugged in, are located in a respective plug-in connector. From the plug-in connector, a loom of cables leads to the respective control devices.
In addition, the support board supports a sensor device by means of which the steering angle of the steering wheel borne by the steering column can be determined. Furthermore, a signal transmission device configured as a so-called helix cable cassette is connected via the support board with the control wires allocated to it.
The known designs for a steering column assembly make it possible in a modular configuration to install various components in the steering-column region in a simple way. In this, the individual components can be attached to the locating device in a confined space, as a functionally pre-tested unit. In addition, by avoiding difficult to handle looms of cables, the installation effort is minimal in the case of the known device.
A problem with the known design of a steering column assembly is the fact that should exchange of the support board become necessary due to a defect, it is necessary to remove the steering wheel and further components, in order to gain access to the support board. For this reason, the support board for example in the device known from DE 44 28 883 C1 is merely configured as a simple lead-type connection between the switches connected to the steering column levers and the control elements which are positioned away from the steering column. For example, by way of these control elements vehicle lights are switched on or off, turn signal indicators are operated, the windscreen wiper device is operated at various speeds or automatic cruise control is activated.